Devices of this type, well known in the prior art, are applied to a very great number of motor vehicles these days to provide assistance with braking.
These devices generally use a reaction disc formed of an elastomeric material, by way of essential reaction means, and this is entirely satisfactory and will undoubtedly continue to be so for a long time.
Such a device is for instance disclosed in document EP-A-0 151 028 which pertains to a tandem booster, i.e. a booster equipped with two amplification stages, the second of which is incorporated into the rigid skirt and controlled in pressure by an electronic circuit, the single reaction means of this tandem booster being nevertheless constituted by a traditional reaction disc formed of an elastomeric material.
However, and despite the traditional nature of the techniques involved, boosters continue to be the subject of substantial amounts of research aiming to optimize their operating characteristics.